The present invention relates to a pressure regulator, in particular to a pressure regulator for an automatic transmission.
Pressure regulators of this type are known from practice and used for example in an automatic transmission of a motor vehicle for actuation of a switching element, such as a coupling. The pressure regulator therefore is connected on the one hand with a hydraulic cylinder-piston unit which serves as an actuator for the coupling, and is connected on the other hand with the coupling representing the consumer.
Such a pressure regulator includes a magnet component which forms the actuator and has a metallic housing with a flange composed of synthetic plastic material and arranged on the metallic housing. The flange forms an injection molded synthetic plastic part, to which the supplier and the consumer are connected it. A guiding sleeve is injection molded in the flange as an insert for connection with the metallic housing of the magnet component group. The guiding sleeve serves for orientation of the magnetic components group.
The magnet components group actuates a valve closing member through a plunger. The valve closing member cooperates with a valve seat and controls the fluid flow from a pressure side to a return side. When the pressure regulator is operated with a small load, the valve seat can be composed of synthetic plastic.
It is further known to make the valve seat for the pressure regulators, which operate with high loads, on an insert composed of metal and surrounded by the injection molded synthetic plastic of the flange.
In both embodiments, in particular when the valve seat is composed of plastic and when the valve seat is formed as the insert, there is a problem that the distance between the magnet components group and the valve seat can change during a temperature change by an expansion or contraction of the synthetic plastic.
It is also known from practice to form the guiding sleeve for orientation and mounting of the magnet component group, which as a rule is formed as a deep drawn part, so that on the one hand the valve seat for the valve closing member actuated by the magnet component group is provided, and on the other hand the radially oriented discharge openings are provided. In this solution the valve seat is integrated with the deep drawn part formed on the guiding sleeve. The deep drawn part formed in this way is however connected with high manufacturing expenses due to the high conversion degree and the requirement to bring the radially oriented discharge openings leading to the return side, in the region of the valve seat on a relatively small inner diameter, for discharging a fluid quantity controlled by the valve closing member.